1. Field of the Invention
This invention relates to aromatic amines and is more particularly concerned with a novel class of alkylated meta-phenylenediamines.
2. Description of the Prior Art
Aromatic amines and particularly aromatic diamines are well known types of compounds finding many applications in the chemical art. Typically, aromatic amines have found utility as starting materials and intermediates in the preparation of other products such as isocyanates, pharmaceuticals, various types of polymers, plastics, and the like. Some of the aromatic diamines find particular utility as curatives in various polymer systems.
Other known classes of aromatic diamines include, typically, the .alpha.,.alpha.'-bis(aminoaryl)xylenes disclosed in U.S. Pat. No. 3,424,795; the limited number of nuclear alkylated aromatic amines and diamines disclosed in U.S. Pat. Nos. 3,678,112; 3,678,113 and 3,862,233; the alkylated toluenediamines and alkylated 4,4'-diaminodiphenylmethanes disclosed in U.S. Pat. Nos. 3,428,610 and 4,218,543; certain meta- or para-isopropenylphenylbenzyl derivatives of aromatic mono- and diamines in German DS No. 17 686 97; and finally simple diamines such as the diaminodiphenylmethanes, toluenediamines, and the like.
I have now discovered a novel class of sterically hindered aromatic meta-phenylene diamines which are easily obtained from readily available starting materials. Further, the aromatic diamines in accordance with the present invention exhibit a wide range of amine basicity or reactivity depending on the extent of the steric hindrance which, in turn, depends on the extent of the substitution in the three possible positions ortho to the two amino groups on the aromatic ring.
Not only can the amine reactivity, i.e. amine basicity, be varied depending on the substitution noted above but other important molecular properties such as compound solubility and melting ranges can be influenced depending on the particular structure and/or isomer mixtures chosen.
The ability to influence amine basicity in the present diamines makes them particularly useful as chain extenders in polyurethane-polyurea polymers which application will be discussed in detail below as part of the present invention.